Any cat-back exhaust will work and not harm your engine. Check out posts in this forum and YouTube for more.

You probably don't want to add a turbo to your engine. It will cost a lot of money, not give you too much power and significantly impact the reliability of your car. If you really wanted a turbo, you should have bought an LGT.

Can't help you on the body kit stuff. Again, the search button is a great tool!